@book{82843,
	title = {A monograph of the western hemisphere bumble bees (Hymenoptera : Apidae; Bombinae); the genus phrobombus, subgenus Cullumane bombus.},
	publisher = {The Entomological Society of Canada},
	year = {1973},
	series = {Memoires of the Entomological Society of Canada; no.91},
	address = {Ottawa}
}